1. Technical Field
The present invention relates to an electrophoretic display and an electronic device.
2. Related Art
An electrophoretic display, which includes a base plate, an opposite plate, and electrophoretic elements having electrophoretic particles dispersed in their respective medium interposed between the base and opposite plates, is well known. For example, in an electrophoretic display disclosed in JP-A-2008-20774, a base plate includes a plurality of pixel electrodes arranged in a matrix, selection transistors each connected to the respective pixel electrodes, capacitors each connected to drains of the respective selection transistors and pixel electrodes. Further, the base plate is configured to form a first capacitor and a second capacitor connected in parallel with each other to store sufficient electric charges in the capacitors.
Through researches conducted by the present inventors, it was found that the intensity difference is likely to appear in a half tone image. Feed-through effect in a selection transistor employed in an electrophoretic display may highly influence the uniformity of image density compared with that in a liquid crystal display. In the electrophoretic display, signal current flows into a capacitor via the selection transistor.
Since the field-through occurs due to a parasitic capacitance of the selection transistor, the influence exerted by the effect can be reduced by increasing a capacitance of a capacitor formed in a pixel. Therefore, as disclosed in JP-A-2008-20774, an electrophoretic display may employ a configuration in which two capacitors are laminated. That is, a capacitor using a gate insulating film is displaced above another capacitor using an interlayer insulating film.
However, the electrophoretic display disclosed in JP-A-2008-20774 has a disadvantage in that, since the upper capacitor is formed in a process different to the process for forming the lower capacitance, the total capacitance of the two capacitors may vary more widely. Further, the electrophoretic display has another disadvantage in that, since the upper capacitor uses a thick interlayer insulating film, it is difficult to increase the capacitance of the upper capacitor.